Added README

README.md

@@ -0,0 +1,77 @@
+# FHIR-Sandbox: SMART on FHIR Integration Application
+
+A Go-based application that demonstrates integration with Electronic Health Record (EHR) systems using the SMART on FHIR protocol.
+
+## Overview
+
+This application implements a SMART on FHIR client that can:
+- Launch from an EHR context
+- Authenticate using OAuth 2.0
+- Retrieve patient information from FHIR servers
+- Display patient details in a structured format
+
+## Prerequisites
+
+- Go 1.16 or higher
+- Access to a SMART on FHIR-compatible EHR system
+- Client credentials (client ID and secret) from your EHR system
+
+## Configuration
+
+The application uses a configuration structure defined in `main.go`. You'll need to configure:
+
+1. SMART App settings:
+   ```go
+   SMARTAppConfig {
+       redirectPath: "http://localhost:8080/auth-redirect",
+       clientID:     "your-client-id",
+       clientSecret: "your-client-secret",
+       scopes:       []string{"launch", "patient/*.read"},
+   }
+2. EHR Client settings:
+   ```go
+    EHRClientsConfig {
+        name:         "EHR_NAME",
+        url:          "https://your-ehr-fhir-endpoint.com",
+        authType:     "auth-2",
+        clientID:     "your-ehr-client-id",
+        clientSecret: "your-ehr-client-secret",
+        patientAPI:   true,
+    }
+    ```
+## Installation
+
+1. Clone the repository:
+```bash
+git clone github.com/AmanTahiliani/fhir-sandbox.git
+cd fhir-sandbox
+```
+2. Install dependencies:
+```bash
+go mod tidy
+```
+
+## Running the Application
+
+1. Start the application:
+```bash
+go run main.go
+```
+2. The application will start and listen on `http://localhost:8080`.
+
+## Endpoints
+- `/` - Root endpoint, displays welcome message
+- `/launch` - SMART launch endpoint
+- `/auth-redirect` - OAuth2 redirect endpoint
+
+## SMART on FHIR Launch Flow
+
+- EHR system initiates launch with parameters:
+    - `launch` - Launch ID
+    - `iss` - FHIR server URL
+- Application authenticates with the EHR:
+    - Retrieves SMART configuration
+    - Initiates OAuth2 flow
+    - Exchanges code for access token
+- Application retrieves and displays patient information
+